The present invention relates generally to the field of environmental monitoring systems. More particularly, the present invention relates to temperature monitoring systems which operate in view of client-specified parameters.
There exist many types of products which are acutely sensitive to the temperature of its immediate environment. Examples of temperature-sensitive products include food and beverages, medical and pharmaceutical products, biological materials, and industrial chemicals and adhesives. When a temperature-sensitive product is exposed to temperatures which exceed predefined parameters, or thresholds, the product is said to have experienced a temperature excursion, or breach. As can be appreciated, having a temperature-sensitive product experience a temperature excursion can compromise the safety, efficacy, potency and/or shelf life of the shipped product, which is highly undesirable.
As a result, the packaging industry has created, in certain circumstances, temperature controlled packaging that is intended to maintain an acceptable temperature range for the product that is being shipped. Although well-known and widely used in the art, temperature controlled packages can experience temperatures outside their intended range. For this reason, it is highly important for the party receiving the temperature-sensitive product to be able to determine whether the product was maintained in its acceptable temperature range throughout the shipping process.
Accordingly, temperature monitoring devices are well-known in the art and are commonly used to track the internal temperatures experienced by the packaged product. Specifically, a temperature monitoring device is typically placed inside the temperature controlled package by the shipping party. After the package has been shipped, the receiving party opens the temperature controlled package and analyzes the temperature monitoring device to determine whether the temperature within the package was maintained within the predefined temperature parameters.
A first type of temperature monitoring device, or indicator, which is well-known and widely used in the art is in the form of a one-time trip switch which triggers a particular, irreversible indicator, such as a color change, when the temperature it experiences breaches a predefined threshold. For example, in U.S. Pat. No. 4,729,671 there is disclosed a disposable monitoring device which is constructed to experience a chemical reaction when exposed to a particular temperature parameter. In response to such a chemical reaction, the indicator visually indicates the temperature excursion by producing a color change using a dye.
This first type of temperature monitoring device is typically used in the following manner. When the shipper is prepared to ship a desired package, the shipper activates the indicator (e.g., by pulling an activating tab) and deposits the indicator onto the shipped item. Once shipped, the recipient of the package can determine whether a particular temperature excursion was experienced by observing the coloration of the indicator.
As can be appreciated, the first type of temperature indicator as described above suffers from a few notable drawbacks.
As a first drawback, the first type of temperature indicator provides the receiving party with very limited information relating to a temperature excursion. In particular, the indicator is only capable of notifying a recipient whether the predefined temperature parameter of the indicator was maintained or breached. The indicator is not capable of informing the receiving party with any of the details of a temperature excursion (e.g., the actual temperatures reached beyond the threshold temperature, the precise time during the shipping period when the temperature excursion occurred, etc.).
As a second drawback, the first type of temperature indicator has been found to be relatively inaccurate (some chemically based temperature indicators have been found to have a degree of uncertainty beyond +/−3° C. for example). The inaccuracies associated with the first type of temperature indicators are often the result of certain external factors (e.g., the shelf life of the marker, proper storage requirements, preconditioned temperatures, etc.) which can significantly alter chemical properties of the indicator.
As a third drawback, the first type of temperature indicator is typically capable of monitoring only one particular temperature threshold and is limited to defining only one direction of breach. (e.g., whether the temperature breaches a particular temperature value by going from cold to hot for a particular period of time). However, in many applications, it is desirable to monitor whether the temperatures within a package are maintained within a temperature range which includes an upper limit as well as a lower limit. In this circumstance, a pair of indicators would be required, one indicator being used to monitor the upper limit of the temperature range and functioning as indicating breach when going from a lower temperature to a higher temperature and the other indicator being used to monitor the lower limit of the temperature range and functioning as indicating breach when going from a higher temperature to a lower temperature.
A second type of temperature monitoring device which is well-known and widely used in the art is commonly referred to as a data logger. A data logger is a complex electronic device which can be programmed with client-specified parameters to monitor the temperature within a container. In use, a data logger is capable of sampling the temperature within a package at user-defined time intervals and, in turn, storing the results of said data samples into a non-volatile memory device located in the data logger. In this manner, the data logger is capable of storing a wide variety of historical data accumulated during its client-specified, monitoring period.
A first type of data logger which is well-known in the art is commonly used in the following manner to track the temperatures within a package during its shipment. The data logger is programmed by the users to log and monitor the internal temperature of a package in view of certain specified parameters (e.g., the upper and lower temperature thresholds for the target temperature range, the frequency of data sampling, etc.). The data logger is then activated by the shipping party (e.g., by depressing an externally accessible button) and packaged within the container. During the shipping process, the data logger measures the internal temperatures within the container. The data accumulated during each sampling period is then stored into a non-volatile memory device located within the logger. Once the package reaches its final destination, the receiving party removes the data logger from the package and either downloads its information to a personal computer (PC) via an electrical connection or ships back the device to the shipping party for subsequent downloading of information.
As can be appreciated, the first type of data logger described above suffers from one notable drawback. Specifically, the first type of data logger described above does not immediately provide the receiving party with information relating to the temperature monitoring data that was accumulated during the tracking period. Rather, it is typically required that the data logger be electronically linked to a PC whereupon the data is further analyzed as to what occurred during shipment. Whether downloaded at the receiver's site or shipped back to the sending party, the process is highly time-consuming and inconvenient. In response to the aforementioned drawback, a second type of data logger which is well-known in the art is provided with a light emitting diode (LED) display to inform the receiving party, by means of a flashing set of LED lights, to alert the receiving party whether or not the received package experienced a breach of predefined temperature ranges within the package. Although somewhat more helpful, this type of data logger suffers from the same drawback as the previous data logger in that its full analysis can only be performed by linking it to a PC, a cumbersome and time consuming task for the receiving party.
In response to the aforementioned drawback, a third type of data logger which is well-known in the art is provided with a display to inform the receiving party with pertinent information relating to the historical data stored thereon. As a result, this type of data logger enables the receiving party to readily determine whether a temperature excursion occurred during the period of shipment by simply viewing the display.
As can be appreciated, the third type of data logger described above suffers from a few notable drawbacks.
As a first drawback, the third type of data logger described above stores all of its accumulated historical data into its internal memory. Because all of the historical data is stored into the data logger memory, it is often difficult to view by means of its LCD the most relevant information stored in the data logger (e.g., data relating to a temperature excursion).
As a second drawback, the third type of data logger described above includes large data storage capabilities. As a result, this type of data logger is often relatively large in size, heavy in weight, and expensive to manufacture.
As a third drawback, the third type of data logger described above is highly susceptible to tampering and manipulation. Specifically, this type of data logger is often provided with a power on/off button which enables an unscrupulous person to temporarily deactivate the data logger.